#!/usr/bin/env nu
# Docker Build Validation Script
# Validates cargo-chef optimization by measuring build times and image sizes
#
# Usage:
#   docker-validate-builds.nu extension-registry
#   docker-validate-builds.nu orchestrator --iterations 3
#
# Environment:
#   PROVISIONING_ROOT - Optional: override project root detection
#
# Metrics:
#   - Cold build (no cache)
#   - Warm build (dependency cache)
#   - Incremental build (source change only)
#   - Image size comparison

# Search up directory tree for provisioning root (helper)
def search-up-for-provisioning [dir: string]: nothing -> string {
    if ($"($dir)/provisioning/schemas/platform" | path exists) {
        $"($dir)/provisioning"
    } else {
        let parent = ($dir | path dirname)
        if $parent == $dir {
            ""
        } else {
            search-up-for-provisioning $parent
        }
    }
}

# Detect provisioning project root
def get-provisioning-root []: nothing -> string {
    # 1. Check environment variable
    if ($env.PROVISIONING_ROOT? != null) {
        return $env.PROVISIONING_ROOT
    }

    # 2. Check if we're in provisioning/ directory
    let cwd = (pwd)
    if ($cwd | path basename) == "provisioning" {
        # We're inside provisioning/, use current dir
        if ("schemas/platform" | path exists) {
            return "."
        }
    }

    # 3. Check if provisioning/ exists as subdirectory
    if ("provisioning/schemas/platform" | path exists) {
        return "provisioning"
    }

    # 4. Search up the directory tree
    let found = (search-up-for-provisioning $cwd)
    if $found != "" {
        return $found
    }

    # 5. Fallback to "provisioning" (will fail with clear error)
    "provisioning"
}

# Run build benchmark for a service
def main [
    service: string,                      # Service to benchmark
    --iterations: int = 1,                # Number of iterations per test
    --skip-cold,                          # Skip cold build (fastest)
    --registry: string = "localhost:5000" # Registry for cache
]: nothing -> record {
    print $"Docker Build Validation: ($service)"
    print "========================================"
    print ""

    # Step 1: Generate Dockerfile
    print "→ Generating Dockerfile..."
    let prov_root = (get-provisioning-root)
    let gen_script = $"($prov_root)/scripts/docker-generate-builds.nu"
    let gen_result = (nu $gen_script $service --mode solo)

    if not $gen_result.ok {
        error make {
            msg: $"Failed to generate Dockerfile: ($gen_result.err)"
        }
    }

    print $"  ✓ Generated: ($gen_result.path)"
    print ""

    let prov_root_build = (get-provisioning-root)
    let build_context = $"($prov_root_build)/platform"
    let dockerfile_path = $gen_result.path
    let image_tag = $"provisioning-($service):test"

    # Step 2: Cold build (no cache)
    let cold_results = if not $skip_cold {
        print "→ Running COLD build (no cache)..."
        print "  This measures full build time including dependencies"

        let cold_times = (1..$iterations | each {|i|
            print $"  Iteration ($i)/($iterations)..."

            # Clear Docker build cache
            docker builder prune --all --force | complete | ignore

            let start = (date now)

            let result = (
                docker buildx build
                    --file $dockerfile_path
                    --tag $"($image_tag)-cold"
                    --no-cache
                    --progress plain
                    $build_context
                | complete
            )

            let end = (date now)
            let duration = (($end - $start) | into int) / 1_000_000_000

            if $result.exit_code != 0 {
                error make {
                    msg: $"Cold build failed: ($result.stderr)"
                }
            }

            print $"    ✓ Completed in ($duration)s"

            $duration
        })

        let avg = ($cold_times | math avg)
        let min = ($cold_times | math min)
        let max = ($cold_times | math max)

        print ""
        print $"  Average: ($avg)s, Min: ($min)s, Max: ($max)s"
        print ""

        {
            avg: $avg,
            min: $min,
            max: $max,
            times: $cold_times
        }
    } else {
        print "→ Skipping COLD build"
        print ""
        null
    }

    # Step 3: Warm build (with dependency cache)
    print "→ Running WARM build (with cargo-chef cache)..."
    print "  This measures build time with cached dependencies"

    let warm_times = (1..$iterations | each {|i|
        print $"  Iteration ($i)/($iterations)..."

        let start = (date now)

        let result = (
            docker buildx build
                --file $dockerfile_path
                --tag $"($image_tag)-warm"
                --cache-from $"type=registry,ref=($registry)/cache:($service)"
                --cache-to $"type=registry,ref=($registry)/cache:($service),mode=max"
                --progress plain
                $build_context
            | complete
        )

        let end = (date now)
        let duration = (($end - $start) | into int) / 1_000_000_000

        if $result.exit_code != 0 {
            error make {
                msg: $"Warm build failed: ($result.stderr)"
            }
        }

        print $"    ✓ Completed in ($duration)s"

        $duration
    })

    let warm_avg = ($warm_times | math avg)
    let warm_min = ($warm_times | math min)
    let warm_max = ($warm_times | math max)

    print ""
    print $"  Average: ($warm_avg)s, Min: ($warm_min)s, Max: ($warm_max)s"
    print ""

    # Step 4: Get image sizes
    print "→ Measuring image sizes..."

    let size_warm = (
        docker images $"($image_tag)-warm" --format "{{.Size}}"
        | str trim
    )

    print $"  Warm build image: ($size_warm)"
    print ""

    # Step 5: Calculate savings
    let results = if not $skip_cold {
        let cache_savings = (($cold_results.avg - $warm_avg) / $cold_results.avg * 100)

        print "Summary:"
        print "========"
        print $"  Cold build (no cache):       ($cold_results.avg)s"
        print $"  Warm build (dep cache):      ($warm_avg)s"
        print $"  Cache savings:               ($cache_savings | into int)%"
        print $"  Image size:                  ($size_warm)"
        print ""

        {
            service: $service,
            cold: $cold_results,
            warm: {
                avg: $warm_avg,
                min: $warm_min,
                max: $warm_max,
                times: $warm_times
            },
            cache_savings_percent: $cache_savings,
            image_size: $size_warm
        }
    } else {
        print "Summary:"
        print "========"
        print $"  Warm build (dep cache):      ($warm_avg)s"
        print $"  Image size:                  ($size_warm)"
        print ""

        {
            service: $service,
            cold: null,
            warm: {
                avg: $warm_avg,
                min: $warm_min,
                max: $warm_max,
                times: $warm_times
            },
            cache_savings_percent: null,
            image_size: $size_warm
        }
    }

    $results
}

# Quick validation (warm build only, 1 iteration)
export def "main quick" [
    service: string
]: nothing -> record {
    main $service --iterations 1 --skip-cold
}

# Full benchmark (cold + warm, 3 iterations)
export def "main full" [
    service: string
]: nothing -> record {
    main $service --iterations 3
}