import { existsSync, mkdirSync, readFileSync, writeFileSync, readdirSync } from "node:fs"
import { join } from "node:path"
import type { WorkflowDef, WorkflowState, TaskRun } from "./types"

export class WorkflowStore {
  private statePath: string
  private runsPath: string
  private defsPath: string

  constructor(worktree: string) {
    const base = join(worktree, ".kirincode", "workflows")
    this.defsPath = base
    this.statePath = join(base, ".state")
    this.runsPath = join(base, ".runs")
    mkdirSync(base, { recursive: true })
    mkdirSync(this.statePath, { recursive: true })
    mkdirSync(this.runsPath, { recursive: true })
  }

  loadDefs(): WorkflowDef[] {
    if (!existsSync(this.defsPath)) return []
    const files = readdirSync(this.defsPath).filter((f) => f.endsWith(".yml") || f.endsWith(".yaml"))
    const seen = new Set<string>()
    const defs: WorkflowDef[] = []
    for (const file of files) {
      try {
        const content = readFileSync(join(this.defsPath, file), "utf-8")
        const def = this.parseYaml(content)
        def.name = def.name || file.replace(/\.(yml|yaml)$/, "")
        if (seen.has(def.name)) continue
        seen.add(def.name)
        defs.push(def)
      } catch {
        // skip unparseable
      }
    }
    return defs
  }

  saveDef(def: WorkflowDef): void {
    // Delete existing .yaml if we're writing .yml (avoid duplicates)
    const yamlPath = join(this.defsPath, `${def.name}.yaml`)
    if (existsSync(yamlPath)) {
      try { require("node:fs").unlinkSync(yamlPath) } catch { /* ignore */ }
    }
    const yml = this.toYaml(def)
    writeFileSync(join(this.defsPath, `${def.name}.yml`), yml, "utf-8")
  }

  loadState(name: string): WorkflowState {
    const p = join(this.statePath, `${name}.json`)
    if (!existsSync(p)) return { name, runCount: 0, enabled: true }
    try {
      return JSON.parse(readFileSync(p, "utf-8"))
    } catch {
      return { name, runCount: 0, enabled: true }
    }
  }

  saveState(state: WorkflowState): void {
    writeFileSync(join(this.statePath, `${state.name}.json`), JSON.stringify(state, null, 2), "utf-8")
  }

  saveRun(run: TaskRun): void {
    writeFileSync(join(this.runsPath, `${run.id}.json`), JSON.stringify(run, null, 2), "utf-8")
  }

  listRuns(limit = 20): TaskRun[] {
    if (!existsSync(this.runsPath)) return []
    return readdirSync(this.runsPath)
      .filter((f) => f.endsWith(".json"))
      .reduce((acc: TaskRun[], f) => {
        try {
          const run = JSON.parse(readFileSync(join(this.runsPath, f), "utf-8")) as TaskRun
          acc.push(run)
        } catch { /* skip corrupt */ }
        return acc
      }, [])
      .sort((a, b) => b.startedAt - a.startedAt)
      .slice(0, limit)
  }

  private parseYaml(s: string): WorkflowDef {
    const def: Record<string, any> = {}
    const lines = s.split("\n")
    let i = 0

    while (i < lines.length) {
      const line = lines[i]
      // Skip comments and empty lines
      if (/^\s*#/.test(line) || /^\s*$/.test(line)) { i++; continue }

      const keyMatch = line.match(/^([\w_-]+):\s*(.*)$/)
      if (!keyMatch) { i++; continue }

      const key = keyMatch[1]
      let value = keyMatch[2]

      // Multiline block scalar (|)
      if (value === "|" || value === "|+") {
        const blockLines: string[] = []
        i++
        while (i < lines.length && /^  /.test(lines[i])) {
          blockLines.push(lines[i].slice(2))
          i++
        }
        def[key] = blockLines.join("\n")
        continue
      }

      // Quoted string
      if ((value.startsWith('"') && value.endsWith('"')) || (value.startsWith("'") && value.endsWith("'"))) {
        def[key] = value.slice(1, -1)
        i++
        continue
      }

      // Array notation
      if (value.startsWith("[") && value.endsWith("]")) {
        def[key] = value.slice(1, -1).split(",").map((x) => x.trim().replace(/^['"]|['"]$/g, ""))
        i++
        continue
      }

      // Booleans
      if (value === "true") { def[key] = true; i++; continue }
      if (value === "false") { def[key] = false; i++; continue }

      // Numbers
      if (/^-?\d+$/.test(value)) { def[key] = parseInt(value); i++; continue }

      // Plain string
      def[key] = value
      i++
    }

    return def as WorkflowDef
  }

  private toYaml(def: WorkflowDef): string {
    const lines: string[] = []
    for (const [k, v] of Object.entries(def)) {
      if (v === undefined) continue
      if (Array.isArray(v)) {
        const items = v.map((x) => `"${String(x).replace(/"/g, '\\"')}"`).join(", ")
        lines.push(`${k}: [${items}]`)
      } else if (typeof v === "boolean") {
        lines.push(`${k}: ${v}`)
      } else if (typeof v === "number") {
        lines.push(`${k}: ${v}`)
      } else if (typeof v === "string") {
        if (v.includes("\n")) {
          lines.push(`${k}: |`)
          for (const l of v.split("\n")) lines.push(`  ${l}`)
        } else {
          const escaped = v.replace(/\\/g, "\\\\").replace(/"/g, '\\"')
          lines.push(`${k}: "${escaped}"`)
        }
      }
    }
    return lines.join("\n") + "\n"
  }
}