import * as fs from "node:fs";
import * as path from "node:path";
import { writeFile, readFile, ensureDir, fileExists } from "../utils/file.js";
import { PipelineStage } from "../types/pipeline.js";
import { MilestoneType } from "../types/config.js";

const CI_DIR = ".ciagent";

export interface ProjectMd {
  name: string;
  coreValue: string;
  requirements: {
    validated: string[];
    active: string[];
    outOfScope: string[];
  };
  constraints: string[];
  context: string;
  keyDecisions: Array<{
    decision: string;
    rationale: string;
    outcome: string;
  }>;
}

export interface RoadmapMd {
  overview: string;
  phases: Array<{
    number: number;
    name: string;
    description: string;
    status: "not_started" | "in_progress" | "complete" | "deferred";
    dependsOn: number[];
    requirements: string[];
    successCriteria: string[];
  }>;
}

export interface RequirementsMd {
  v1: Array<{
    category: string;
    items: Array<{ id: string; description: string }>;
  }>;
  v2: Array<{
    category: string;
    items: Array<{ id: string; description: string }>;
  }>;
  outOfScope: Array<{ feature: string; reason: string }>;
  traceability: Array<{
    requirement: string;
    phase: number;
    status: "pending" | "in_progress" | "complete" | "blocked";
  }>;
}

export interface ArchitectureMd {
  overview: string;
  components: Array<{
    name: string;
    description: string;
    boundaries: string;
    dependsOn: string[];
  }>;
  dataFlow: string;
  buildOrder: string[];
}

export interface ProjectEntry {
  slug: string;
  name: string;
  default?: boolean;
}

export class CIAgentFiles {
  private projectPath: string;
  private projectSlug: string;

  constructor(projectPath: string, projectSlug?: string) {
    this.projectPath = projectPath;
    this.projectSlug = projectSlug || "";
  }

  private get ciDir(): string {
    return path.join(this.projectPath, CI_DIR);
  }

  private get projectDir(): string {
    if (this.projectSlug) {
      return path.join(this.ciDir, this.projectSlug);
    }
    return this.ciDir;
  }

  setProjectSlug(slug: string): void {
    this.projectSlug = slug;
  }

  getProjectSlug(): string {
    return this.projectSlug;
  }

  ensureCIDir(): void {
    ensureDir(this.ciDir);
  }

  ensureProjectDir(): void {
    this.ensureCIDir();
    if (this.projectSlug) {
      ensureDir(this.projectDir);
    }
  }

  isInitialized(): boolean {
    return fileExists(path.join(this.ciDir, "config.json"));
  }

  isMultiProject(): boolean {
    if (!this.isInitialized()) return false;
    const config = this.readConfigJson();
    const projects = config?.projects;
    return Array.isArray(projects) && (projects as unknown[]).length > 0;
  }

  listProjects(): ProjectEntry[] {
    if (!this.isInitialized()) return [];

    const config = this.readConfigJson();
    if (Array.isArray(config?.projects) && config.projects.length > 0) {
      return config.projects;
    }

    const subdirs = this.getProjectSubdirectories();
    if (subdirs.length > 0) {
      return subdirs.map((slug) => {
        const projMd = this.readProjectMdForSlug(slug);
        return {
          slug,
          name: projMd?.name || slug,
          default: subdirs.length === 1,
        };
      });
    }

    return [{ slug: "default", name: "Default Project", default: true }];
  }

  getActiveProject(): string {
    if (!this.isInitialized()) return "";

    const config = this.readConfigJson();
    if (config && typeof config.active_project === "string") return config.active_project;

    const projects = this.listProjects();
    const defaultProject = projects.find((p) => p.default);
    if (defaultProject) return defaultProject.slug;

    return projects.length > 0 ? projects[0].slug : "";
  }

  setActiveProject(slug: string): void {
    this.ensureCIDir();
    const config = this.readConfigJson() || {};
    config.active_project = slug;
    this.writeConfigJson(config);
  }

  addProject(slug: string, name: string, isDefault: boolean = false): void {
    this.ensureCIDir();
    const config = this.readConfigJson() || {};

    if (!Array.isArray(config.projects)) {
      config.projects = [];
    }

    if ((config.projects as unknown[]).some((p: unknown) => (p as ProjectEntry).slug === slug)) return;

    (config.projects as ProjectEntry[]).push({ slug, name, default: isDefault });

    if (isDefault || (config.projects as unknown[]).length === 1) {
      config.active_project = slug;
    }

    this.writeConfigJson(config);
    ensureDir(path.join(this.ciDir, slug));
  }

  needsMigration(): boolean {
    if (!this.isInitialized()) return false;
    if (this.isMultiProject()) return false;

    const hasFlatFiles = fileExists(path.join(this.ciDir, "PROJECT.md"));
    const hasSubdirs = this.getProjectSubdirectories().length > 0;

    return hasFlatFiles && !hasSubdirs;
  }

  migrateFlatToProject(slug: string): void {
    if (!this.needsMigration()) return;

    this.ensureCIDir();
    const projectDir = path.join(this.ciDir, slug);
    ensureDir(projectDir);

    const filesToMove = ["PROJECT.md", "ARCHITECTURE.md", "ROADMAP.md", "REQUIREMENTS.md"];
    for (const file of filesToMove) {
      const src = path.join(this.ciDir, file);
      const dest = path.join(projectDir, file);
      if (fileExists(src) && !fileExists(dest)) {
        const content = readFile(src);
        if (content) {
          writeFile(dest, content);
        }
      }
    }

    const config = this.readConfigJson() || {};
    config.projects = [{ slug, name: slug, default: true }];
    config.active_project = slug;
    this.writeConfigJson(config);
  }

  private getProjectSubdirectories(): string[] {
    if (!fs.existsSync(this.ciDir)) return [];

    try {
      return fs.readdirSync(this.ciDir, { withFileTypes: true })
        .filter((d) => d.isDirectory())
        .filter((d) => {
          const projectFile = path.join(this.ciDir, d.name, "PROJECT.md");
          return fileExists(projectFile);
        })
        .map((d) => d.name);
    } catch {
      return [];
    }
  }

  private readConfigJson(): Record<string, unknown> | null {
    const content = readFile(path.join(this.ciDir, "config.json"));
    if (!content) return null;
    try {
      return JSON.parse(content) as Record<string, unknown>;
    } catch {
      return null;
    }
  }

  private writeConfigJson(config: Record<string, unknown>): void {
    writeFile(path.join(this.ciDir, "config.json"), JSON.stringify(config, null, 2));
  }

  private readProjectMdForSlug(slug: string): ProjectMd | null {
    const content = readFile(path.join(this.ciDir, slug, "PROJECT.md"));
    if (!content) return null;
    return this.parseProjectMd(content);
  }

  readProjectMd(): ProjectMd | null {
    const content = readFile(path.join(this.projectDir, "PROJECT.md"));
    if (!content) return null;
    return this.parseProjectMd(content);
  }

  writeProjectMd(project: ProjectMd, reason: string): void {
    this.ensureProjectDir();
    const lines: string[] = [
      `# ${project.name}`,
      "",
      "## What This Is",
      "",
      project.coreValue,
      "",
      "## Requirements",
      "",
      "### Validated",
      "",
      ...project.requirements.validated.map((r) => `- ✓ ${r}`),
      "",
      "### Active",
      "",
      ...project.requirements.active.map((r) => `- [ ] ${r}`),
      "",
      "### Out of Scope",
      "",
      ...project.requirements.outOfScope.map((r) => `- ${r}`),
      "",
      "## Context",
      "",
      project.context,
      "",
      "## Constraints",
      "",
      ...project.constraints.map((c) => `- ${c}`),
      "",
      "## Key Decisions",
      "",
      "| Decision | Rationale | Outcome |",
      "|----------|-----------|---------|",
      ...project.keyDecisions.map(
        (d) => `| ${d.decision} | ${d.rationale} | ${d.outcome} |`
      ),
      "",
    ];

    writeFile(path.join(this.projectDir, "PROJECT.md"), lines.join("\n"));
  }

  readRoadmapMd(): RoadmapMd | null {
    const content = readFile(path.join(this.projectDir, "ROADMAP.md"));
    if (!content) return null;
    return this.parseRoadmapMd(content);
  }

  writeRoadmapMd(roadmap: RoadmapMd): void {
    this.ensureProjectDir();
    const lines: string[] = [
      "# Roadmap",
      "",
      "## Overview",
      "",
      roadmap.overview,
      "",
      "## Phases",
      "",
      ...roadmap.phases.map(
        (p) => `- [${p.status === "complete" ? "x" : " "}] **Phase ${p.number}: ${p.name}** - ${p.description}`
      ),
      "",
      "## Phase Details",
      "",
    ];

    for (const phase of roadmap.phases) {
      lines.push(`### Phase ${phase.number}: ${phase.name}`);
      lines.push(`**Goal**.: ${phase.description}`);
      lines.push(`**Depends on**: ${phase.dependsOn.length > 0 ? phase.dependsOn.map((d) => `Phase ${d}`).join(", ") : "Nothing"}`);
      lines.push(`**Requirements**: ${phase.requirements.length > 0 ? phase.requirements.join(", ") : "None"}`);
      lines.push("**Success Criteria**:");
      for (const sc of phase.successCriteria) {
        lines.push(`1. ${sc}`);
      }
      lines.push(`**Status**: ${phase.status}`);
      lines.push("");
    }

    writeFile(path.join(this.projectDir, "ROADMAP.md"), lines.join("\n"));
  }

  readRequirementsMd(): RequirementsMd | null {
    const content = readFile(path.join(this.projectDir, "REQUIREMENTS.md"));
    if (!content) return null;
    return this.parseRequirementsMd(content);
  }

  writeRequirementsMd(requirements: RequirementsMd): void {
    this.ensureProjectDir();
    const lines: string[] = [
      "# Requirements",
      "",
      "## v1 Requirements",
      "",
    ];

    for (const cat of requirements.v1) {
      lines.push(`### ${cat.category}`);
      lines.push("");
      for (const item of cat.items) {
        lines.push(`- [ ] **${item.id}**: ${item.description}`);
      }
      lines.push("");
    }

    lines.push("## v2 Requirements");
    lines.push("");
    for (const cat of requirements.v2) {
      lines.push(`### ${cat.category}`);
      lines.push("");
      for (const item of cat.items) {
        lines.push(`- **${item.id}**: ${item.description}`);
      }
      lines.push("");
    }

    lines.push("## Out of Scope");
    lines.push("");
    lines.push("| Feature | Reason |");
    lines.push("|---------|--------|");
    for (const item of requirements.outOfScope) {
      lines.push(`| ${item.feature} | ${item.reason} |`);
    }
    lines.push("");

    lines.push("## Traceability");
    lines.push("");
    lines.push("| Requirement | Phase | Status |");
    lines.push("|-------------|-------|--------|");
    for (const t of requirements.traceability) {
      lines.push(`| ${t.requirement} | Phase ${t.phase} | ${t.status} |`);
    }

    writeFile(path.join(this.projectDir, "REQUIREMENTS.md"), lines.join("\n"));
  }

  readArchitectureMd(): ArchitectureMd | null {
    const content = readFile(path.join(this.projectDir, "ARCHITECTURE.md"));
    if (!content) return null;
    return this.parseArchitectureMd(content);
  }

  writeArchitectureMd(architecture: ArchitectureMd): void {
    this.ensureProjectDir();
    const lines: string[] = [
      "# Architecture",
      "",
      "## Overview",
      "",
      architecture.overview,
      "",
      "## Components",
      "",
    ];

    for (const comp of architecture.components) {
      lines.push(`### ${comp.name}`);
      lines.push(`- **Description**: ${comp.description}`);
      lines.push(`- **Boundaries**: ${comp.boundaries}`);
      lines.push(`- **Depends on**: ${comp.dependsOn.length > 0 ? comp.dependsOn.join(", ") : "None"}`);
      lines.push("");
    }

    lines.push("## Data Flow");
    lines.push("");
    lines.push(architecture.dataFlow);
    lines.push("");

    lines.push("## Build Order");
    lines.push("");
    for (const step of architecture.buildOrder) {
      lines.push(`1. ${step}`);
    }

    writeFile(path.join(this.projectDir, "ARCHITECTURE.md"), lines.join("\n"));
  }

  updateRequirementStatus(reqId: string, status: "pending" | "in_progress" | "complete" | "blocked"): void {
    const reqs = this.readRequirementsMd();
    if (!reqs) return;

    for (const t of reqs.traceability) {
      if (t.requirement === reqId) {
        t.status = status;
      }
    }

    this.writeRequirementsMd(reqs);
  }

  updatePhaseStatus(phaseNumber: number, status: "not_started" | "in_progress" | "complete" | "deferred"): void {
    const roadmap = this.readRoadmapMd();
    if (!roadmap) return;

    for (const phase of roadmap.phases) {
      if (phase.number === phaseNumber) {
        phase.status = status;
      }
    }

    this.writeRoadmapMd(roadmap);
  }

  getMilestoneType(): MilestoneType {
    const roadmap = this.readRoadmapMd();
    if (!roadmap) return "nfr";

    const nfrTypes: string[] = ["fix", "chore", "docs", "perf", "refactor", "test"];
    const schemaBreakKeywords: string[] = ["refactor", "rewrite", "rearchitecture", "migrate", "restructure"];
    let hasFeature = false;
    let hasSchemaBreak = false;

    for (const phase of roadmap.phases) {
      if (phase.status === "in_progress" || phase.status === "not_started" || phase.status === "complete") {
        const phaseName = phase.name.toLowerCase();
        const isNfr = nfrTypes.some((t) => phaseName.includes(t)) || phaseName.includes("bug") || phaseName.includes("tune") || phaseName.includes("refresh");
        if (!isNfr) hasFeature = true;
        if (schemaBreakKeywords.some((k) => phaseName.includes(k))) hasSchemaBreak = true;
      }
    }

    if (hasSchemaBreak) return "schema-breaking";
    if (hasFeature) return "feature";
    return "nfr";
  }

  isNfrMilestone(): boolean {
    return this.getMilestoneType() === "nfr";
  }

  private parseProjectMd(content: string): ProjectMd {
    return {
      name: this.extractSection(content, "# ") || "Unknown",
      coreValue: this.extractSection(content, "## What This Is") || "",
      requirements: {
        validated: this.extractListItems(content, "### Validated"),
        active: this.extractListItems(content, "### Active"),
        outOfScope: this.extractListItems(content, "### Out of Scope"),
      },
      constraints: this.extractListItems(content, "## Constraints"),
      context: this.extractSection(content, "## Context") || "",
      keyDecisions: [],
    };
  }

  private parseRoadmapMd(content: string): RoadmapMd {
    const overview = this.extractSection(content, "## Overview") || "";

    const phases: RoadmapMd["phases"] = [];
    const phaseRegex = /### Phase (\d+): (.+)/g;
    let match;

    while ((match = phaseRegex.exec(content)) !== null) {
      const number = parseInt(match[1], 10);
      const name = match[2].trim();
      const sectionStart = match.index + match[0].length;
      const nextPhase = content.indexOf("\n### Phase ", sectionStart);
      const nextH2 = content.indexOf("\n## ", sectionStart);
      const sectionEnd = Math.min(
        nextPhase >= 0 ? nextPhase : content.length,
        nextH2 >= 0 ? nextH2 : content.length
      );
      const section = content.slice(sectionStart, sectionEnd);

      const goalMatch = section.match(/\*\*Goal\.?\*\*:\s*(.+)/);
      const statusMatch = section.match(/\*\*Status\*\*:\s*(.+)/);
      const reqMatch = section.match(/\*\*Requirements\*\*:\s*(.+)/);
      const depsMatch = section.match(/\*\*Depends on\*\*:\s*(.+)/);

      const statusVal = statusMatch ? statusMatch[1].trim() : "not_started";
      const validStatuses = ["not_started", "in_progress", "complete", "deferred"] as const;

      phases.push({
        number,
        name,
        description: goalMatch ? goalMatch[1].trim() : "",
        status: validStatuses.includes(statusVal as typeof validStatuses[number])
          ? (statusVal as RoadmapMd["phases"][number]["status"])
          : "not_started",
        dependsOn: depsMatch && depsMatch[1].trim() !== "Nothing"
          ? depsMatch[1].split(",").map((d: string) => parseInt(d.trim().replace(/Phase /g, ""), 10)).filter((n: number) => !isNaN(n))
          : [],
        requirements: reqMatch && reqMatch[1].trim() !== "None"
          ? reqMatch[1].split(",").map((r: string) => r.trim()).filter(Boolean)
          : [],
        successCriteria: [],
      });
    }

    return { overview, phases };
  }

  private parseRequirementsMd(content: string): RequirementsMd {
    const v1: RequirementsMd["v1"] = [];
    const v2: RequirementsMd["v2"] = [];

    const v1Section = this.extractSection(content, "## v1 Requirements");
    if (v1Section) {
      const categoryBlocks = v1Section.split(/\n### /).filter(Boolean);
      for (const block of categoryBlocks) {
        const lines = block.split("\n");
        const category = lines[0].trim();
        const items: Array<{ id: string; description: string }> = [];

        for (const line of lines.slice(1)) {
          const tableMatch = line.match(/^\|\s*([A-Z]+-\d+)\s*\|\s*(.+?)\s*\|/);
          if (tableMatch) {
            items.push({ id: tableMatch[1], description: tableMatch[2] });
            continue;
          }
          const listMatch = line.match(/^\s*-?\s*\*?\s*\[?\s*\*?\s*([A-Z]+-\d+)[\]:\s*]*(.+)/);
          if (listMatch) {
            items.push({ id: listMatch[1], description: listMatch[2].trim() });
          }
        }

        if (items.length > 0) {
          v1.push({ category, items });
        }
      }
    }

    const v2Section = this.extractSection(content, "## v2 Requirements");
    if (v2Section) {
      const categoryBlocks = v2Section.split(/\n### /).filter(Boolean);
      for (const block of categoryBlocks) {
        const lines = block.split("\n");
        const category = lines[0].trim();
        const items: Array<{ id: string; description: string }> = [];

        for (const line of lines.slice(1)) {
          const tableMatch = line.match(/^\|\s*([A-Z]+-\d+)\s*\|\s*(.+?)\s*\|/);
          if (tableMatch) {
            items.push({ id: tableMatch[1], description: tableMatch[2] });
            continue;
          }
          const listMatch = line.match(/^\s*-?\s*\*?\s*\[?\s*\*?\s*([A-Z]+-\d+)[\]:\s*]*(.+)/);
          if (listMatch) {
            items.push({ id: listMatch[1], description: listMatch[2].trim() });
          }
        }

        if (items.length > 0) {
          v2.push({ category, items });
        }
      }
    }

    const outOfScope: RequirementsMd["outOfScope"] = [];
    const outSection = this.extractSection(content, "## Out of Scope");
    if (outSection) {
      const tableRows = outSection.split("\n").filter((line) => /^\|/.test(line) && !line.includes("---") && !line.includes("Feature"));
      for (const row of tableRows) {
        const cols = row.split("|").map((c) => c.trim()).filter(Boolean);
        if (cols.length >= 2) {
          outOfScope.push({ feature: cols[0], reason: cols[1] });
        }
      }
      if (outOfScope.length === 0) {
        const listItems = this.extractListItems(content, "## Out of Scope");
        for (const item of listItems) {
          outOfScope.push({ feature: item, reason: "" });
        }
      }
    }

    const traceability: RequirementsMd["traceability"] = [];
    const traceSection = this.extractSection(content, "## Traceability");
    if (traceSection) {
      const activeHeader = traceSection.includes("Active Milestone")
        ? "## v0.5 Requirements (Active Milestone)"
        : content.includes("## v1 Requirements")
          ? "## v1 Requirements"
          : undefined;

      const tableRows = traceSection.split("\n").filter((line) => /^\|/.test(line) && !line.includes("---") && !line.includes("Requirement") && !line.includes("REQ-ID"));
      for (const row of tableRows) {
        const cols = row.split("|").map((c) => c.trim()).filter(Boolean);
        if (cols.length >= 3) {
          const req = cols[0];
          const phaseStr = cols[1];
          const phaseMatch = phaseStr.match(/(\d+)/);
          const phase = phaseMatch ? parseInt(phaseMatch[1], 10) : 0;
          const statusStr = cols[2].toLowerCase();
          const status = ["pending", "in_progress", "complete", "blocked", "covered"].includes(statusStr)
            ? (statusStr === "covered" ? "complete" : statusStr as "pending" | "in_progress" | "complete" | "blocked")
            : "pending";
          traceability.push({ requirement: req, phase, status });
        }
      }
    }

    const allReqIds = new Set<string>();
    for (const cat of [...v1, ...v2]) {
      for (const item of cat.items) {
        allReqIds.add(item.id);
      }
    }
    for (const t of traceability) {
      allReqIds.add(t.requirement);
    }
    const coveredInTrace = new Set(traceability.filter((t) => t.status === "complete").map((t) => t.requirement));
    for (const reqId of allReqIds) {
      if (!coveredInTrace.has(reqId)) {
        traceability.push({ requirement: reqId, phase: 0, status: "pending" });
      }
    }

    return { v1, v2, outOfScope, traceability };
  }

  private parseArchitectureMd(content: string): ArchitectureMd {
    const overview = this.extractSection(content, "## Overview") || "";

    const components: ArchitectureMd["components"] = [];
    const section = content;
    const componentRegex = /###\s+(.+)/g;
    let compMatch;

    const h3Positions: Array<{ name: string; start: number }> = [];
    while ((compMatch = componentRegex.exec(section)) !== null) {
      h3Positions.push({ name: compMatch[1].trim(), start: compMatch.index + compMatch[0].length });
    }

    for (let i = 0; i < h3Positions.length; i++) {
      const name = h3Positions[i].name;
      const start = h3Positions[i].start;
      const end = i + 1 < h3Positions.length ? h3Positions[i + 1].start - (content.substring(h3Positions[i + 1].start - 4, h3Positions[i + 1].start) === "### " ? 4 : 0) : content.length;
      const block = content.slice(start, end);

      const descMatch = block.match(/[-*]\s*\*?\*?(?:Description|description)\*?\*?\s*[:：]\s*(.+)/);
      const boundaryMatch = block.match(/[-*]\s*\*?\*?(?:Boundaries|boundaries)\*?\*?\s*[:：]\s*(.+)/);
      const depsMatch = block.match(/[-*]\s*\*?\*?(?:Depends on|depends on|Dependencies)\*?\*?\s*[:：]\s*(.+)/);

      components.push({
        name,
        description: descMatch ? descMatch[1].trim() : "",
        boundaries: boundaryMatch ? boundaryMatch[1].trim() : "",
        dependsOn: depsMatch
          ? depsMatch[1].split(",").map((d: string) => d.trim().replace(/\*\*/g, "")).filter(Boolean)
          : [],
      });
    }

    const dataFlow = this.extractSection(content, "## Data Flow")
      || this.extractSection(content, "## Data flow")
      || "";

    const buildOrder: string[] = [];
    const buildSection = this.extractSection(content, "## Build Order");
    if (buildSection) {
      const listItems = buildSection
        .split("\n")
        .filter((line) => /^\d+\./.test(line.trim()))
        .map((line) => line.trim().replace(/^\d+\.\s*/, ""));
      buildOrder.push(...listItems);
    }

    return { overview, components, dataFlow, buildOrder };
  }

  private extractSection(content: string, header: string): string | null {
    const headerIdx = content.indexOf(header);
    if (headerIdx < 0) return null;

    const startIdx = headerIdx + header.length;
    const nextHeaderIdx = content.indexOf("\n## ", startIdx);
    const endIdx = nextHeaderIdx >= 0 ? nextHeaderIdx : content.length;

    return content.slice(startIdx, endIdx).trim();
  }

  private extractListItems(content: string, header: string): string[] {
    const section = this.extractSection(content, header);
    if (!section) return [];

    return section
      .split("\n")
      .filter((line) => line.trim().startsWith("-"))
      .map((line) => line.replace(/^-\s*(?:\[[ x]\]\s*)?(?:✓\s*)?/, "").trim())
      .filter(Boolean);
  }
}