import { spawn } from "child_process"
import { Tiles } from "../src/Models/TileRange"

export class PmTilesExtractGenerator {
    private readonly _targetDir: string
    private readonly _sourceFile: string
    private readonly _executeableLocation: string

    constructor(
        sourceFile: string,
        targetDir: string,
        executeableLocation: string = "/data/pmtiles"
    ) {
        this._sourceFile = sourceFile
        this._targetDir = targetDir
        this._executeableLocation = executeableLocation
    }

    startProcess(script: string, captureStdioChunks?: (string: string) => void): Promise<void> {
        return new Promise((resolve, reject) => {
            const child = spawn(this._executeableLocation, script.split(" "), {
                stdio: captureStdioChunks === undefined ? "ignore" : ["pipe", "pipe", "pipe"],
                cwd: this._targetDir,
            })

            if (captureStdioChunks !== undefined) {
                child.stdout.on("data", (data) => {
                    captureStdioChunks(data)
                })
            }

            /*child.stderr.on('data', data => {
                console.error(`stderr: ${data}`);
            });*/

            child.on("close", (code) => {
                if (code === 0) resolve()
                else reject(new Error(`Process exited with code ${code}`))
            })

            child.on("error", reject)
        })
    }

    getFilename(z: number, x: number, y: number) {
        return `${this._targetDir}/${z}/${x}/${y}.pmtiles`
    }

    async generateArchive(z: number, x: number, y: number, maxzoom?: number): Promise<string> {
        const [[max_lat, min_lon], [min_lat, max_lon]] = Tiles.tile_bounds(z, x, y)
        let maxzoomflag = ""
        if (maxzoom !== undefined) {
            maxzoomflag = " --maxzoom=" + maxzoom
        }
        const outputFileName = this.getFilename(z, x, y)
        await this.startProcess(
            `extract ${
                this._sourceFile
            } --download-threads=1 --minzoom=${z}${maxzoomflag} --bbox=${[
                min_lon,
                min_lat + 0.0001,
                max_lon,
                max_lat,
            ].join(",")} ${outputFileName}`
        )
        return outputFileName
    }
}