// Command dumpschema regenerates docs/DATABASE.md from the real, live
// database schema -- it opens a fresh temp database through store.Open
// (the exact same code path geniusrund itself uses) and introspects
// sqlite_master, so the generated documentation can never drift from what
// the app actually creates. Run it after any change to
// internal/store/schema.sql:
//
//	go run ./cmd/dumpschema
package main

import (
	"fmt"
	"log"
	"os"
	"path/filepath"
	"strings"

	"geniusrun/backend/internal/store"
)

type schemaEntry struct {
	typ     string // "table" or "view"
	name    string
	tblName string
	sql     string
}

func main() {
	tmpDir, err := os.MkdirTemp("", "geniusrun-dumpschema")
	must(err)
	defer os.RemoveAll(tmpDir)

	db, err := store.Open(filepath.Join(tmpDir, "schema-check.db"))
	must(err)
	defer db.Close()

	rows, err := db.Query(`
		SELECT type, name, tbl_name, sql FROM sqlite_master
		WHERE sql IS NOT NULL AND name NOT LIKE 'sqlite_%'
		ORDER BY rowid`)
	must(err)
	defer rows.Close()

	var tables, views []schemaEntry
	indexesByTable := map[string][]schemaEntry{}

	for rows.Next() {
		var e schemaEntry
		must(rows.Scan(&e.typ, &e.name, &e.tblName, &e.sql))
		switch e.typ {
		case "table":
			tables = append(tables, e)
		case "view":
			views = append(views, e)
		case "index":
			indexesByTable[e.tblName] = append(indexesByTable[e.tblName], e)
		}
	}
	must(rows.Err())

	var b strings.Builder
	b.WriteString("# geniusrun database schema\n\n")
	b.WriteString("Generated from the live schema via `go run ./cmd/dumpschema` -- do not hand-edit. ")
	b.WriteString("The source of truth is `backend/internal/store/schema.sql`; regenerate this file after changing it.\n\n")

	b.WriteString("## Tables\n\n")
	for _, t := range tables {
		fmt.Fprintf(&b, "- [`%s`](#%s)\n", t.name, t.name)
	}
	b.WriteString("\n")

	for _, t := range tables {
		fmt.Fprintf(&b, "## `%s`\n\n", t.name)
		fmt.Fprintf(&b, "```sql\n%s;\n```\n\n", t.sql)
		if idxs := indexesByTable[t.name]; len(idxs) > 0 {
			b.WriteString("Indexes:\n\n```sql\n")
			for _, idx := range idxs {
				fmt.Fprintf(&b, "%s;\n", idx.sql)
			}
			b.WriteString("```\n\n")
		}
	}

	if len(views) > 0 {
		b.WriteString("## Views\n\n")
		for _, v := range views {
			fmt.Fprintf(&b, "### `%s`\n\n", v.name)
			fmt.Fprintf(&b, "```sql\n%s;\n```\n\n", v.sql)
		}
	}

	outPath := "../docs/DATABASE.md"
	must(os.WriteFile(outPath, []byte(b.String()), 0644))
	log.Printf("wrote %s", outPath)
}

func must(err error) {
	if err != nil {
		log.Fatal(err)
	}
}