package provider

import (
	"context"
	"errors"
	"sort"

	"proxy-pool/internal/platform/lifecycle"
)

var ErrInvalidFleet = errors.New("invalid Provider fleet")

type Fleet struct {
	runtimes []*UpstreamRuntime
	group    *lifecycle.Group
}

func NewFleet(runtimes ...*UpstreamRuntime) (*Fleet, error) {
	if len(runtimes) == 0 {
		return nil, ErrInvalidFleet
	}
	seen := make(map[string]struct{}, len(runtimes))
	owned := make([]*UpstreamRuntime, len(runtimes))
	for index, runtime := range runtimes {
		if runtime == nil || runtime.config.Provider.UpstreamID == "" {
			return nil, ErrInvalidFleet
		}
		if _, exists := seen[runtime.config.Provider.UpstreamID]; exists {
			return nil, ErrInvalidFleet
		}
		seen[runtime.config.Provider.UpstreamID] = struct{}{}
		owned[index] = runtime
	}
	sort.Slice(owned, func(left, right int) bool {
		return owned[left].ID() < owned[right].ID()
	})
	runners := make([]lifecycle.Runner, len(owned))
	for index, runtime := range owned {
		runners[index] = runtime
	}
	group, err := lifecycle.NewGroup(runners...)
	if err != nil {
		return nil, errors.Join(ErrInvalidFleet, err)
	}
	return &Fleet{runtimes: owned, group: group}, nil
}

func (fleet *Fleet) Run(ctx context.Context) error {
	if fleet == nil || ctx == nil || len(fleet.runtimes) == 0 || fleet.group == nil {
		return ErrInvalidFleet
	}
	return fleet.group.Run(ctx)
}

func (fleet *Fleet) IDs() []string {
	if fleet == nil {
		return nil
	}
	ids := make([]string, len(fleet.runtimes))
	for index, runtime := range fleet.runtimes {
		ids[index] = runtime.ID()
	}
	return ids
}